[REG 4.7.2->5.0.0] DirectWrite fix for QTBUG-18748 went missing too

The fix for QTBUG-18748 removed a series of +1 and -1 adjustments to height calculations. However, the DirectWrite adjustment was made to the pre-Lighthouse qfontenginedirectwrite.cpp instead of the new qwindowsfontenginedirectwrite.cpp and has since been lost, resulting in incorrect descent & height calculations.